Optical imaging lens and electronic device comprising the same

ABSTRACT

An optical imaging lens includes: a first, second and third lens element. The first lens element has a positive refracting power, and has an object-side surface with a convex part in a vicinity of the optical axis, and a convex part in a vicinity of its periphery. The second lens element has a positive refracting power, and has an object-side surface with a concave part in a vicinity of the optical axis, and a concave part in a vicinity of its periphery, and has an image-side surface with a convex part in a vicinity of the optical axis. The third lens element has negative refracting power, and has an image-side surface with a concave part in a vicinity of the optical axis, and a convex part in a vicinity of its periphery.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Taiwan Patent Application No.103137265, filed on Oct. 28, 2014, the contents of which are herebyincorporated by reference in their entirety for all purposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to an optical imaging lens setand an electronic device which includes such optical imaging lens set.Specifically speaking, the present invention is directed to an opticalimaging lens set of three lens elements and an electronic device whichincludes such optical imaging lens set.

2. Description of the Prior Art

In recent years, the popularity of mobile phones and digital camerasmakes the sizes of various portable electronic products reduce quickly,and so does the size of the photography modules. The current trend ofresearch is to develop an optical imaging lens set of a shorter lengthwith uncompromised good quality. The most important characteristics ofan optical imaging lens set are image quality and size.

Both U.S. Pat. No. 7,436,605 and U.S. Pat. No. 7,813,056 discloseoptical imaging lens sets of three lens elements. However, in bothpatents mentioned above, the first lens element has negative refractivepower, the second lens element has positive refractive power. Thisarrangement cannot achieve good optical performance. Besides, the sizeof the optical imaging lens set is too big (about 7˜8 mm) to satisfy thespecification requirements of consumer electronics products.

Therefore, how to reduce the total length of a photographic device, butstill maintain good optical performance, is an important researchobjective.

SUMMARY OF THE INVENTION

In light of the above, the present invention proposes an optical imaginglens set that is lightweight, has a low production cost, has an enlargedhalf of field of view, has a high resolution and has high image quality.The optical imaging lens set of three lens elements of the presentinvention has an aperture stop, a first lens element, a second lenselement and a third lens element sequentially from an object side to animage side along an optical axis.

An optical imaging lens includes: a first, second and third lenselement, the first lens element has a positive refracting power, and hasan object-side surface with a convex part in a vicinity of the opticalaxis, and a convex part in a vicinity of its periphery, the second lenselement has a positive refracting power, and has an object-side surfacewith a concave part in a vicinity of the optical axis, and a concavepart in a vicinity of its periphery, and has an image-side surface witha convex part in a vicinity of the optical axis, the third lens elementhas negative refracting power, and has an image-side surface with aconcave part in a vicinity of the optical axis, and a convex part in avicinity of its periphery. Besides, the Abbe number of the first lenselement is V1; the Abbe number of the second lens element is V2; theAbbe number of the third lens element is V3, and in the optical imaginglens set of three lens elements of the present invention, therelationship of |V1−V2|≦10.0 and 20.0≦|V1−V3| are satisfied. Inaddition, the optical imaging lens set does not include any lens elementwith refractive power other than said first, second and third lenselements.

In the optical imaging lens set of three lens elements of the presentinvention, an air gap AG12 along the optical axis is disposed betweenthe first lens element and the second lens element, an air gap AG23along the optical axis is disposed between the second lens element andthe third lens element, and the sum of both of two air gaps betweenadjacent lens elements from the first lens element to the third lenselement along the optical axis is AAG, AAG=AG12+AG23.

In the optical imaging lens set of three lens elements of the presentinvention, the first lens element has a first lens element thickness T1along the optical axis, the second lens element has a second lenselement thickness T2 along the optical axis, the third lens element hasa third lens element thickness T3 along the optical axis, and the totalthickness of all the lens elements in the optical imaging lens set alongthe optical axis is ALT, ALT=T1+T2+T3.

Besides, the distance between an object-side surface of the first lenselement to an image plane is TTL, the effective focal length of theoptical imaging lens set is EFL, the distance between the image-sidesurface of the third lens element to an image plane along the opticalaxis is BFL (back focal length).

In addition, further defining: The focal length of the first lenselement is f1; The focal length of the second lens element is f2; Thefocal length of the third lens element is f3.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship AAG/T1≦1.2 is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship 1.4≦T2/AG12 is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship AG12/T1≦1.0 is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship AAG/T3≦1.1 is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship T2/T1≦1.45 is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship 4.6≦EFL/AAG is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship 1.25≦T2/AAG is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship 3.5≦ALT/AG12 is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship EFL/T1≦5.5 is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship 3.0≦ALT/AAG is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship ALT/T1≦3.6 is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship AG12/T3≦1.0 is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship 5.5≦EFL/AG12 is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship |f1/EFL|+|f2/EFL|≦2.0 is satisfied.

In the optical imaging lens set of three lens elements of the presentinvention, the relationship |f1/EFL|+|f3/EFL|≦2.0 is satisfied.

The present invention also proposes an electronic device which includesthe optical imaging lens set as described above. The electronic deviceincludes a case and an image module disposed in the case. The imagemodule includes an optical imaging lens set as described above, a barrelfor the installation of the optical imaging lens set, a module housingunit for the installation of the barrel, a substrate for theinstallation of the module housing unit, and an image sensor disposed onthe substrate and at an image side of the optical imaging lens set.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-5 illustrates the methods for determining the surface shapes andfor determining one region is a region in a vicinity of the optical axisor the region in a vicinity of its circular periphery of one lenselement.

FIG. 6 illustrates a first example of the optical imaging lens set ofthe present invention.

FIG. 7A illustrates the longitudinal spherical aberration on the imageplane of the first example.

FIG. 7B illustrates the astigmatic aberration on the sagittal directionof the first example.

FIG. 7C illustrates the astigmatic aberration on the tangentialdirection of the first example.

FIG. 7D illustrates the distortion aberration of the first example.

FIG. 8 illustrates a second example of the optical imaging lens set ofthree lens elements of the present invention.

FIG. 9A illustrates the longitudinal spherical aberration on the imageplane of the second example.

FIG. 9B illustrates the astigmatic aberration on the sagittal directionof the second example.

FIG. 9C illustrates the astigmatic aberration on the tangentialdirection of the second example.

FIG. 9D illustrates the distortion aberration of the second example.

FIG. 10 illustrates a third example of the optical imaging lens set ofthree lens elements of the present invention.

FIG. 11A illustrates the longitudinal spherical aberration on the imageplane of the third example.

FIG. 11B illustrates the astigmatic aberration on the sagittal directionof the third example.

FIG. 11C illustrates the astigmatic aberration on the tangentialdirection of the third example.

FIG. 11D illustrates the distortion aberration of the third example.

FIG. 12 illustrates a fourth example of the optical imaging lens set ofthree lens elements of the present invention.

FIG. 13A illustrates the longitudinal spherical aberration on the imageplane of the fourth example.

FIG. 13B illustrates the astigmatic aberration on the sagittal directionof the fourth example.

FIG. 13C illustrates the astigmatic aberration on the tangentialdirection of the fourth example.

FIG. 13D illustrates the distortion aberration of the fourth example.

FIG. 14 illustrates a fifth example of the optical imaging lens set ofthree lens elements of the present invention.

FIG. 15A illustrates the longitudinal spherical aberration on the imageplane of the fifth example.

FIG. 15B illustrates the astigmatic aberration on the sagittal directionof the fifth example.

FIG. 15C illustrates the astigmatic aberration on the tangentialdirection of the fifth example.

FIG. 15D illustrates the distortion aberration of the fifth example.

FIG. 16 illustrates a first preferred example of the portable electronicdevice with an optical imaging lens set of the present invention.

FIG. 17 illustrates a second preferred example of the portableelectronic device with an optical imaging lens set of the presentinvention.

FIG. 18 shows the optical data of the first example of the opticalimaging lens set.

FIG. 19 shows the aspheric surface data of the first example.

FIG. 20 shows the optical data of the second example of the opticalimaging lens set.

FIG. 21 shows the aspheric surface data of the second example.

FIG. 22 shows the optical data of the third example of the opticalimaging lens set.

FIG. 23 shows the aspheric surface data of the third example.

FIG. 24 shows the optical data of the fourth example of the opticalimaging lens set.

FIG. 25 shows the aspheric surface data of the fourth example.

FIG. 26 shows the optical data of the fifth example of the opticalimaging lens set.

FIG. 27 shows the aspheric surface data of the fifth example.

FIG. 28 shows some important ratios in the examples.

DETAILED DESCRIPTION

Before the detailed description of the present invention, the firstthing to be noticed is that in the present invention, similar (notnecessarily identical) elements are labeled as the same numeralreferences. In the present specification, the description “a lenselement having positive refracting power (or negative refractive power)”means that the paraxial refractive power of the lens element in Gaussianoptics is positive (or negative). The description “An object-side (orimage-side) surface of a lens element” only includes a specific regionof that surface of the lens element where imaging rays are capable ofpassing through that region, namely the clear aperture of the surface.The aforementioned imaging rays can be classified into two types, chiefray Lc and marginal ray Lm. Taking a lens element depicted in FIG. 1 asan example, the lens element is rotationally symmetric, where theoptical axis I is the axis of symmetry. The region A of the lens elementis defined as “a part in a vicinity of the optical axis”, and the regionC of the lens element is defined as “apart in a vicinity of a peripheryof the lens element”. Besides, the lens element may also have anextending part E extended radially and outwardly from the region C,namely the part outside of the clear aperture of the lens element. Theextending part E is usually used for physically assembling the lenselement into an optical imaging lens system. Under normal circumstances,the imaging rays would not pass through the extending part E becausethose imaging rays only pass through the clear aperture. The structuresand shapes of the aforementioned extending part E are only examples fortechnical explanation, the structures and shapes of lens elements shouldnot be limited to these examples. Note that the extending parts of thelens element surfaces depicted in the following embodiments arepartially omitted.

The following criteria are provided for determining the shapes and theportions of lens element surfaces set forth in the presentspecification. These criteria mainly determine the boundaries ofportions under various circumstances including the portion in a vicinityof the optical axis, the portion in a vicinity of a periphery of a lenselement surface, and other types of lens element surfaces such as thosehaving multiple portions.

1. FIG. 1 is a radial cross-sectional view of a lens element. Beforedetermining boundaries of those aforesaid portions, two referentialpoints should be defined first, central point and conversion point. Thecentral point of a surface of a lens element is a point of intersectionof that surface and the optical axis. The conversion point is a point ona surface of a lens element, where the tangent line of that point isperpendicular to the optical axis. Additionally, if multiple conversionpoints appear on one single surface, then these conversion points aresequentially named along the radial direction of the surface withnumbers starting from the first conversion point. For instance, thefirst conversion point (closest one to the optical axis), the secondconversion point, and the Nth conversion point (farthest one to theoptical axis within the scope of the clear aperture of the surface). Theportion of a surface of the lens element between the central point andthe first conversion point is defined as the portion in a vicinity ofthe optical axis. The portion located radially outside of the Nthconversion point (but still within the scope of the clear aperture) isdefined as the portion in a vicinity of a periphery of the lens element.In some embodiments, there are other portions existing between theportion in a vicinity of the optical axis and the portion in a vicinityof a periphery of the lens element; the numbers of portions depend onthe numbers of the conversion point (s). In addition, the radius of theclear aperture (or a so-called effective radius) of a surface is definedas the radial distance from the optical axis I to a point ofintersection of the marginal ray Lm and the surface of the lens element.

2. Referring to FIG. 2, determining the shape of a portion is convex orconcave depends on whether a collimated ray passing through that portionconverges or diverges. That is, while applying a collimated ray to aportion to be determined in terms of shape, the collimated ray passingthrough that portion will be bended and the ray itself or its extensionline will eventually meet the optical axis. The shape of that portioncan be determined by whether the ray or its extension line meets(intersects) the optical axis (focal point) at the object-side orimage-side. For instance, if the ray itself intersects the optical axisat the image side of the lens element after passing through a portion,i.e. the focal point of this ray is at the image side (see point R inFIG. 2), the portion will be determined as having a convex shape. On thecontrary, if the ray diverges after passing through a portion, theextension line of the ray intersects the optical axis at the object sideof the lens element, i.e. the focal point of the ray is at the objectside (see point M in FIG. 2), that portion will be determined as havinga concave shape. Therefore, referring to FIG. 2, the portion between thecentral point and the first conversion point has a convex shape, theportion located radially outside of the first conversion point has aconcave shape, and the first conversion point is the point where theportion having a convex shape changes to the portion having a concaveshape, namely the border of two adjacent portions. Alternatively, thereis another common way for a person with ordinary skill in the art totell whether a portion in a vicinity of the optical axis has a convex orconcave shape by referring to the sign of an “R” value, which is the(paraxial) radius of curvature of a lens surface. The R value which iscommonly used in conventional optical design software such as Zemax andCodeV. The R value usually appears in the lens data sheet in thesoftware. For an object-side surface, positive R means that theobject-side surface is convex, and negative R means that the object-sidesurface is concave. Conversely, for an image-side surface, positive Rmeans that the image-side surface is concave, and negative R means thatthe image-side surface is convex. The result found by using this methodshould be consistent as by using the other way mentioned above, whichdetermines surface shapes by referring to whether the focal point of acollimated ray is at the object side or the image side.

3. For none conversion point cases, the portion in a vicinity of theoptical axis is defined as the portion between 0˜50% of the effectiveradius (radius of the clear aperture) of the surface, whereas theportion in a vicinity of a periphery of the lens element is defined asthe portion between 50˜100% of effective radius (radius of the clearaperture) of the surface.

Referring to the first example depicted in FIG. 3, only one conversionpoint, namely a first conversion point, appears within the clearaperture of the image-side surface of the lens element. Portion I is aportion in a vicinity of the optical axis, and portion II is a portionin a vicinity of a periphery of the lens element. The portion in avicinity of the optical axis is determined as having a concave surfacedue to the R value at the image-side surface of the lens element ispositive. The shape of the portion in a vicinity of a periphery of thelens element is different from that of the radially inner adjacentportion, i.e. the shape of the portion in a vicinity of a periphery ofthe lens element is different from the shape of the portion in avicinity of the optical axis; the portion in a vicinity of a peripheryof the lens element has a convex shape.

Referring to the second example depicted in FIG. 4, a first conversionpoint and a second conversion point exist on the object-side surface(within the clear aperture) of a lens element. In which portion I is theportion in a vicinity of the optical axis, and portion III is theportion in a vicinity of a periphery of the lens element. The portion ina vicinity of the optical axis has a convex shape because the R value atthe object-side surface of the lens element is positive. The portion ina vicinity of a periphery of the lens element (portion III) has a convexshape. What is more, there is another portion having a concave shapeexisting between the first and second conversion point (portion II).

Referring to a third example depicted in FIG. 5, no conversion pointexists on the object-side surface of the lens element. In this case, theportion between 0˜50% of the effective radius (radius of the clearaperture) is determined as the portion in a vicinity of the opticalaxis, and the portion between 50˜100% of the effective radius isdetermined as the portion in a vicinity of a periphery of the lenselement. The portion in a vicinity of the optical axis of theobject-side surface of the lens element is determined as having a convexshape due to its positive R value, and the portion in a vicinity of aperiphery of the lens element is determined as having a convex shape aswell.

As shown in FIG. 6, the optical imaging lens set 1 of three lenselements of the present invention, sequentially located from an objectside 2 (where an object is located) to an image side 3 along an opticalaxis 4, have an aperture stop 80, a first lens element 10, a second lenselement 20, a third lens element 30, a filter 72 and an image plane 71.Generally speaking, the first lens element 10, the second lens element20 and the third lens element 30 may be made of a transparent plasticmaterial and each has an appropriate refractive power, but the presentinvention is not limited to this. There are exclusively three lenselements with refractive power in the optical imaging lens set 1 of thepresent invention. The optical axis 4 is the optical axis of the entireoptical imaging lens set 1, and the optical axis of each of the lenselements coincides with the optical axis of the optical imaging lens set1.

Furthermore, the optical imaging lens set 1 includes an aperture stop(ape. stop) 80 disposed in an appropriate position. In FIG. 6, theaperture stop 80 is disposed on the object side 2 of the first lenselement 10. When light emitted or reflected by an object (not shown)which is located at the object side 2 enters the optical imaging lensset 1 of the present invention, it forms a clear and sharp image on theimage plane 71 at the image side 3 after passing through the aperturestop 80, the first lens element 10, the second lens element 20, thethird lens element 30 and the filter 72.

In the embodiments of the present invention, the optional filter 72 maybe a filter of various suitable functions, for example, the filter 72may be an infrared cut filter (IR cut filter), placed between the thirdlens element 30 and the image plane 71. The filter 72 is made of glass.

Each lens element in the optical imaging lens set 1 of the presentinvention has an object-side surface facing toward the object side 2 aswell as an image-side surface facing toward the image side 3. Forexample, the first lens element 10 has a first object-side surface 11and a first image-side surface 12; the second lens element 20 has asecond object-side surface 21 and a second image-side surface 22; thethird lens element 30 has a third object-side surface 31 and a thirdimage-side surface 32. In addition, each object-side surface andimage-side surface in the optical imaging lens set 1 of the presentinvention has a part in a vicinity of its circular periphery (circularperiphery part) away from the optical axis 4 as well as a part in avicinity of the optical axis (optical axis part) close to the opticalaxis 4.

Each lens element in the optical imaging lens set 1 of the presentinvention further has a central thickness on the optical axis 4. Forexample, the first lens element 10 has a first lens element thicknessT1, the second lens element 20 has a second lens element thickness T2,and the third lens element 30 has a third lens element thickness T3.Therefore, the total thickness of all the lens elements in the opticalimaging lens set 1 along the optical axis 4 is ALT, ALT=T1+T2+T3.

In addition, between two adjacent lens elements in the optical imaginglens set 1 of the present invention there is an air gap along theoptical axis 4. For example, an air gap AG12 is disposed between thefirst lens element 10 and the second lens element 20, an air gap AG23 isdisposed between the second lens element 20 and the third lens element30. Therefore, the sum of both of two air gaps between adjacent lenselements from the first lens element 10 to the third lens element 30along the optical axis 4 is AAG, AAG=AG12+AG23.

In addition, the distance between the first object-side surface 11 ofthe first lens element 10 to the image plane 71, namely the total lengthof the optical imaging lens set along the optical axis 4 is TTL; theeffective focal length of the optical imaging lens set is EFL, thedistance between the image-side surface 32 of the third lens element 30to the image plane 71 along the optical axis 4 is BFL.

Besides, further defining: The focal length of the first lens element 10is f1; The focal length of the second lens element 20 is f2; The focallength of the third lens element 30 is f3.

First Example

Please refer to FIG. 6 which illustrates the first example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 7A for the longitudinal spherical aberration on the image plane 71of the first example; please refer to FIG. 7B for the astigmatic fieldaberration on the sagittal direction; please refer to FIG. 7C for theastigmatic field aberration on the tangential direction, and pleaserefer to FIG. 7D for the distortion aberration. The Y axis of thespherical aberration in each example is “field of view” for 1.0. The Yaxis of the astigmatic field and the distortion in each example standfor “image height”. The image height is 1.08 mm.

The optical imaging lens set 1 of the first example has three lenselements 10 to 30 made of a plastic material and having refractivepower. The optical imaging lens set 1 also has an aperture stop 80, afilter 72, and an image plane 71. The aperture stop 80 is providedbetween the object-side 2 and the first lens element 10. The filter 72may be used for preventing specific wavelength light (such as theinfrared light) from reaching the image plane and adversely affectingthe imaging quality.

The first lens element 10 has positive refractive power. The firstobject-side surface 11 facing toward the object side 2 is a convexsurface, having a convex part 13 in the vicinity of the optical axis anda convex part 14 in a vicinity of its circular periphery. The firstimage-side surface 12 facing toward the image side 3 has a concave part16 in the vicinity of the optical axis and a convex part 17 in avicinity of its circular periphery.

The second lens element 20 has positive refractive power. The secondobject-side surface 21 facing toward the object side 2 has a concavepart 23 in the vicinity of the optical axis and a concave part 24 in avicinity of its circular periphery. The second image-side surface 22facing toward the image side 3 has a convex part 26 in the vicinity ofthe optical axis and a concave part 27 in a vicinity of its circularperiphery.

The third lens element 30 has negative refractive power. The thirdobject-side surface 31 facing toward the object side 2 has a concavepart 33 in the vicinity of the optical axis and a concave part 34 in avicinity of its circular periphery. The third image-side surface 32facing toward the image side 3 has a concave part 36 in the vicinity ofthe optical axis and a convex part 37 in a vicinity of its circularperiphery. The filter 72 may be disposed between the third lens element30 and the image plane 71.

In the optical imaging lens element 1 of the present invention, theobject-side surfaces 11/21/31 and image-side surfaces 12/22/32 are allaspherical. These aspheric coefficients are defined according to thefollowing formula:

${Z(Y)} = {{\frac{Y^{2}}{R}/\left( {1 + \sqrt{1 - {\left( {1 + K} \right)\frac{Y^{2}}{R^{2}}}}} \right)} + {\sum\limits_{i = 1}^{n}{a_{2\; i} \times Y^{2\; i}}}}$

In which:

R represents the curvature radius of the lens element surface;

Z represents the depth of an aspherical surface (the perpendiculardistance between the point of the aspherical surface at a distance Yfrom the optical axis and the tangent plane of the vertex on the opticalaxis of the aspherical surface);

Y represents a vertical distance from a point on the aspherical surfaceto the optical axis;

K is a conic constant; and

a2i is the aspheric coefficient of the 2i order.

The optical data of the first example of the optical imaging lens set 1are shown in FIG. 18 while the aspheric surface data are shown in FIG.19. In the present examples of the optical imaging lens set, thef-number of the entire optical lens element system is Fno, HFOV standsfor the half field of view which is half of the field of view of theentire optical lens element system, and the unit for the curvatureradius, the thickness and the focal length is in millimeters (mm). Thelength of the optical imaging lens set (the distance from the firstobject-side surface 11 of the first lens element 10 to the image plane71) is 2.1016 mm. The image height is 1.08 mm, and HFOV is 33.85degrees. Some important ratios of the first example are as follows:

AAG/T1=0.2553

AG12/T1=0.2000

T2/T1=0.8293

T2/AAG=3.2491

EFL/T1=2.9501

ALT/T1=2.3822

EFL/AG12=14.7530

T2/AG12=4.1475

AAG/T3=0.4617

EFL/AAG=11.5574

ALT/AG12=11.9134

ALT/AAG=3.1423

AG12/T3=0.3617

|f1/EFL|+|f2/EFL|=1.7046

|f1/EFL|+|f3/EFL|=1.5686

Second Example

Please refer to FIG. 8 which illustrates the second example of theoptical imaging lens set 1 of the present invention. It is noted thatfrom the second example to the following examples, in order to simplifythe figures, only the components different from what the first examplehas and the basic lens elements will be labeled in figures. Othercomponents that are the same as what the first example has, such as theobject-side surface, the image-side surface, the part in a vicinity ofthe optical axis and the part in a vicinity of its circular peripherywill be omitted in the following example. Please refer to FIG. 9A forthe longitudinal spherical aberration on the image plane 71 of thesecond example; please refer to FIG. 9B for the astigmatic aberration onthe sagittal direction; please refer to FIG. 9C for the astigmaticaberration on the tangential direction, and please refer to FIG. 9D forthe distortion aberration. The components in the second example aresimilar to those in the first example, but the optical data such as thecurvature radius, the refractive power, the lens thickness, the lensfocal length, the aspheric surface or the back focal length in thisexample are different from the optical data in the first example, and inthis example, the first image-side surface 12 of the first lens element10 has a concave part 16A in the vicinity of the optical axis and aconcave part 17A in a vicinity of its circular periphery; the secondimage-side surface 22 of the second lens element 20 has a convex part26A in the vicinity of the optical axis and a convex part 27A in avicinity of its circular periphery. The optical data of the secondexample of the optical imaging lens set are shown in FIG. 20 while theaspheric surface data are shown in FIG. 21. The length of the opticalimaging lens set is 2.1058 mm. The image height is 1.08 mm, HFOV is32.49 degrees. Some important ratios of the second example are asfollows:

AAG/T1=1.1140

AG12/T1=0.9997

T2/T1=1.4001

T2/AAG=1.2568

EFL/T1=5.4987

ALT/T1=3.5007

EFL/AG12=5.5005

T2/AG12=1.4006

AAG/T3=1.0126

EFL/AAG=4.9358

ALT/AG12=3.5018

ALT/AAG=6.1090

AG12/T3=0.9086

|f1/EFL|+|f2/EFL|=1.7539

|f1/EFL|+|f3/EFL|=1.7212

Third Example

Please refer to FIG. 10 which illustrates the third example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 11A for the longitudinal spherical aberration on the image plane 71of the third example; please refer to FIG. 11B for the astigmaticaberration on the sagittal direction; please refer to FIG. 11C for theastigmatic aberration on the tangential direction, and please refer toFIG. 11D for the distortion aberration. The components in the thirdexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example,and in this example, the third object-side surface 31 of the third lenselement 30 has a convex part 33B in the vicinity of the optical axis anda concave part 34B in a vicinity of its circular periphery. The opticaldata of the third example of the optical imaging lens set are shown inFIG. 22 while the aspheric surface data are shown in FIG. 23. The lengthof the optical imaging lens set is 2.0498 mm. The image height is 1.08mm, HFOV is 34.38 degrees. Some important ratios of the third exampleare as follows:

AAG/T1=0.3335

AG12/T1=0.2818

T2/T1=0.5201

T2/AAG=1.5594

EFL/T1=2.6701

ALT/T1=2.0374

EFL/AG12=9.4743

T2/AG12=1.8454

AAG/T3=0.6447

EFL/AAG=8.0062

ALT/AG12=7.2292

ALT/AAG=9.3021

AG12/T3=0.5448

|f1/EFL|+|f2/EFL|=1.8705

|f1/EFL|+|f3/EFL|=1.8552

Fourth Example

Please refer to FIG. 12 which illustrates the fourth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 13A for the longitudinal spherical aberration on the image plane 71of the fourth example; please refer to FIG. 13B for the astigmaticaberration on the sagittal direction; please refer to FIG. 13C for theastigmatic aberration on the tangential direction, and please refer toFIG. 13D for the distortion aberration. The components in the fourthexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example,and in this example, the first image-side surface 12 of the first lenselement 10 has a convex part 16C in the vicinity of the optical axis anda convex part 17C in a vicinity of its circular periphery; the secondimage-side surface 22 of the second lens element 20 has a convex part26C in the vicinity of the optical axis and a convex part 27C in avicinity of its circular periphery; the third object-side surface 31 ofthe third lens element 30 is a has a convex part 33C in the vicinity ofthe optical axis and a concave part 34C in a vicinity of its circularperiphery. The optical data of the fourth example of the optical imaginglens set are shown in FIG. 24 while the aspheric surface data are shownin FIG. 25. The length of the optical imaging lens set is 2.1009 mm. Theimage height is 1.08 mm, HFOV is 34.50 degrees. Some important ratios ofthe fourth example are as follows:

AAG/T1=0.2500

AG12/T1=0.1955

T2/T1=0.8168

T2/AAG=3.2680

EFL/T1=2.8225

ALT/T1=2.3251

EFL/AG12=14.4373

T2/AG12=4.1783

AAG/T3=0.4918

EFL/AAG=11.2919

ALT/AG12=11.8932

ALT/AAG=3.1306

AG12/T3=0.3846

|f1/EFL|+|f2/EFL|=1.8334

|f1/EFL|+|f3/EFL|=1.6510

Fifth Example

Please refer to FIG. 14 which illustrates the fifth example of theoptical imaging lens set 1 of the present invention. Please refer toFIG. 15A for the longitudinal spherical aberration on the image plane 71of the fifth example; please refer to FIG. 15B for the astigmaticaberration on the sagittal direction; please refer to FIG. 15C for theastigmatic aberration on the tangential direction, and please refer toFIG. 15D for the distortion aberration. The components in the fifthexample are similar to those in the first example, but the optical datasuch as the curvature radius, the refractive power, the lens thickness,the lens focal length, the aspheric surface or the back focal length inthis example are different from the optical data in the first example,and in this example, the second image-side surface 22 of the second lenselement 20 has a convex part 26D in the vicinity of the optical axis anda convex part 27D in a vicinity of its circular periphery. The opticaldata of the fifth example of the optical imaging lens set are shown inFIG. 26 while the aspheric surface data are shown in FIG. 27. The lengthof the optical imaging lens set is 2.1033 mm. The image height is 1.08mm, HFOV is 33.44 degrees. Some important ratios of the fifth exampleare as follows:

AAG/T1=0.3027

AG12/T1=0.2542

T2/T1=0.4854

T2/AAG=1.6034

EFL/T1=2.5996

ALT/T1=2.0188

EFL/AG12=10.2279

T2/AG12=1.9096

AAG/T3=0.5675

EFL/AAG=8.5879

ALT/AG12=7.9427

ALT/AAG=6.6692

AG12/T3=0.4765

|f1/EFL|+|f2/EFL|=1.8068

|f1/EFL|+|f3/EFL|=1.7270

Some important ratios in each example are shown in FIG. 28. In light ofthe above examples, the inventors observe the following features:

The first lens element and the second lens element have positiverefractive power, to provide the needed refractive power for the opticalimaging lens set. The third lens element has negative refractive power,to correct aberration. In addition, the aperture stop is disposedbetween the object side and the first lens element, helping to collectthe image light and decreasing the total length of the optical imaginglens set. Besides, the first object-side surface of the first lenselement has a convex part in a vicinity of the optical axis and a convexpart in a vicinity of its circular periphery and can help to collect theimage light; the second object-side surface of the second lens elementhas a concave part in a vicinity of the optical axis and a concave partin a vicinity of its circular periphery; the second image-side surfaceof the second lens element has a convex part in a vicinity of theoptical axis; the third image-side surface of the third lens element hasa concave part in a vicinity of the optical axis and a convex part in avicinity of its circular periphery, where each of the surfaces matcheach other, in order to improve the aberration.

In addition, the inventors discover that there are some better ratioranges for different data according to the above various importantratios. Better ratio ranges help the designers to design the betteroptical performance and an effectively reduced length of a practicallypossible optical imaging lens set. For example:AAG/T1≦1.2, AG12/T1≦1.0, T2/AAG≧1.25, EFL/AG12≧5.5, T2/AG12≧1.4,AAG/T3≦1.1, EFL/AAG≧4.6, ALT/AG12≧3.5, ALT/AAG≧3.0, AG12/T3≦1.0:  (1)

T1, T2, T3 are the thicknesses of the first lens element, the secondlens element and the third lens element along said optical axisrespectively. ALT is the total thickness of said first lens element,said second lens element and said third lens element along said opticalaxis. AG12 is an air gap between said first lens element and said secondlens element along the optical axis. AAG is the sum of both of two airgaps between adjacent lens elements from the first lens element to thethird lens element along the optical axis. Decreasing any valuesmentioned above can help in shrinking the total length of the opticalimaging lens set. But considering the difficulties of during themanufacturing process, T1, T2, T3 and ALT cannot be shrunk unlimitedly,but AG12 and AAG can be shrunk more compared with T1, T2, T3 and ALT.Since T1, T2, T3 and ALT should be maintained within a relatively largevalue, and AG12 and AAG can be decreased more, so AAG/T1, AG12/T1,AAG/T3 and AG12/T3 should preferably be small. On the other hand,T2/AAG, EFL/AG12, T2/AG12, EFL/AAG, ALT/AG12 and ALT/AAG shouldpreferably be large. If the relationship AAG/T1≦1.2 is satisfied,ideally, it is suggested that the range may be 0.2˜1.2; If therelationship AG12/T1≦1.0 is satisfied, ideally, it is suggested that therange may be 0.1˜1.0; If the relationship T2/AAG≧1.25 is satisfied,ideally, it is suggested that the range may be 1.25˜4.0; If therelationship EFL/AG12≧5.5 is satisfied, ideally, it is suggested thatthe range may be 5.5˜20.0; If the relationship T2/AG12≧1.4 is satisfied,ideally, it is suggested that the range may be 1.4˜5.0; If therelationship AAG/T3≦1.1 is satisfied, ideally, it is suggested that therange may be 0.3˜1.1; If the relationship EFL/AAG≧4.6 is satisfied,ideally, it is suggested that the range may be 4.6˜12.0; If therelationship ALT/AG12≧3.5 is satisfied, ideally, it is suggested thatthe range may be 3.5˜15.0; If the relationship ALT/AAG≧3.0 is satisfied,ideally, it is suggested that the range may be 3.0˜10.0; If therelationship AG12/T3≦1.0 is satisfied, ideally, it is suggested that therange may be 0.3˜1.0.T2/T1≦1.45, ALT/T1≦3.6, EFL/T1≦5.5:  (2)

T1, T2, T3 and ALT should be maintained within a suitable value range.Otherwise, the total length cannot be thinned if every lens elements hastoo big thickness, or it's difficult to manufacture the optical imaginglens set if every lens elements have too small thickness. If therelationship T2/T1≦1.45 is satisfied, ideally, it is suggested that therange may be 0.4˜1.45; If the relationship ALT/T1≦3.6 is satisfied,ideally, it is suggested that the range may be 1.5˜3.6; If therelationship EFL/T1≦5.5 is satisfied, ideally, it is suggested that therange may be 2.0˜5.5.|f1/EFL|+|f2/EFL|≦2.0, |f1/EFL|+|f3/EFL|≦2.0:  (3)

The above relationships should be satisfied, to ensure that the firstlens element, the second lens element and the third lens element haveenough refractive power. If the relationship |f1/EFL|+|f2/EFL|≦2.0 issatisfied, ideally, it is suggested that the range may be 1.5˜2.0; Ifthe relationship |f1/EFL|+|f3/EFL|≦2.0 is satisfied, ideally, it issuggested that the range may be 1.5˜2.0.

The optical imaging lens set 1 of the present invention may be appliedto an electronic device, such as game consoles or driving recorders.Please refer to FIG. 16. FIG. 16 illustrates a first preferred exampleof the optical imaging lens set 1 of the present invention for use in aportable electronic device 100. The electronic device 100 includes acase 110, and an image module 120 mounted in the case 110. A drivingrecorder is illustrated in FIG. 16 as an example, but the electronicdevice 100 is not limited to a driving recorder.

As shown in FIG. 16, the image module 120 includes the optical imaginglens set 1 as described above. FIG. 16 illustrates the aforementionedfirst example of the optical imaging lens set 1. In addition, theportable electronic device 100 also contains a barrel 130 for theinstallation of the optical imaging lens set 1, a module housing unit140 for the installation of the barrel 130, a substrate 172 for theinstallation of the module housing unit 140 and an image sensor 70disposed at the substrate 172, and at the image side 3 of the opticalimaging lens set 1. The image sensor 70 in the optical imaging lens set1 may be an electronic photosensitive element, such as a charge coupleddevice or a complementary metal oxide semiconductor element. The imageplane 71 forms at the image sensor 70.

The image sensor 70 used here is a product of chip on board (COB)package rather than a product of the conventional chip scale package(CSP) so it is directly attached to the substrate 172, and protectiveglass is not needed in front of the image sensor 70 in the opticalimaging lens set 1, but the present invention is not limited to this.

To be noticed in particular, the optional filter 72 may be omitted inother examples although the optional filter 72 is present in thisexample. The case 110, the barrel 130, and/or the module housing unit140 may be a single element or consist of a plurality of elements, butthe present invention is not limited to this.

Each one of the three lens elements 10, 20 and 30 with refractive poweris installed in the barrel 130 with air gaps disposed between twoadjacent lens elements in an exemplary way. The module housing unit 140has a lens element housing 141, and an image sensor housing 146installed between the lens element housing 141 and the image sensor 70.However in other examples, the image sensor housing 146 is optional. Thebarrel 130 is installed coaxially along with the lens element housing141 along the axis I-I′, and the barrel 130 is provided inside of thelens element housing 141.

Please also refer to FIG. 17 for another application of theaforementioned optical imaging lens set 1 in a portable electronicdevice 200 in the second preferred example. The main differences betweenthe portable electronic device 200 in the second preferred example andthe portable electronic device 100 in the first preferred example are:the lens element housing 141 has a first seat element 142, a second seatelement 143, a coil 144 and a magnetic component 145. The first seatelement 142 is for the installation of the barrel 130, exteriorlyattached to the barrel 130 and disposed along the axis I-I′. The secondseat element 143 is disposed along the axis I-I′ and surrounds theexterior of the first seat element 142. The coil 144 is provided betweenthe outside of the first seat element 142 and the inside of the secondseat element 143. The magnetic component 145 is disposed between theoutside of the coil 144 and the inside of the second seat element 143.

The first seat element 142 may pull the barrel 130 and the opticalimaging lens set 1 which is disposed inside of the barrel 130 to movealong the axis I-I′, namely the optical axis 4 in FIG. 6. The imagesensor housing 146 is attached to the second seat element 143. Thefilter 72, such as an infrared filter, is installed at the image sensorhousing 146. Other details of the portable electronic device 200 in thesecond preferred example are similar to those of the portable electronicdevice 100 in the first preferred example so they are not elaboratedagain.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. An optical imaging lens set, from an object sidetoward an image side in order along an optical axis comprising: anaperture stop, a first lens element, a second lens element and a thirdlens element, said first to third lens elements having an object-sidesurface facing toward the object side as well as an image-side surfacefacing toward the image side, wherein: the first lens element haspositive refractive power, an object-side surface with a convex part ina vicinity of the optical axis, and a convex part in a vicinity of itsperiphery; the second lens element has positive refractive power, anobject-side surface with a concave part in a vicinity of the opticalaxis, and a concave part in a vicinity of its periphery, an image-sidesurface with a convex part in a vicinity of the optical axis; and thethird lens element has negative refractive power, an image-side surfacewith a concave part in a vicinity of the optical axis, and a convex partin a vicinity of its periphery; wherein a sum of both of two air gapsAAG between each lens element from said first lens element to said thirdlens element along the optical axis, a thickness T1 of said first lenselement along said optical axis, a thickness T2 of said second lenselement along said optical axis, a thickness T3 of said third lenselement along said optical axis, an Abbe number V1 of the first lenselement, an Abbe number V2 of the second lens element, and an Abbenumber V3 of the third lens element satisfy the relationshipsAAG/T3≦1.1, T2/T1≦1.45, AAG/T1≦1.2, and |V1−V2|≦10.0, in addition, theoptical imaging lens set does not include any lens element withrefractive power other than said first, second and third lens elements.2. The optical imaging lens set of claim 1, wherein an air gap AG12between said first lens elements and said second lens element along saidoptical axis a relationship 1.4≦T2/AG12≦5.0.
 3. The optical imaging lensset of claim 1, wherein an air gap AG12 between said first lens elementsand said second lens element along said optical axis satisfies arelationship AG12/T1≦1.0.
 4. The optical imaging lens set of claim 1,wherein an effective focal length EFL of the optical imaging lens setsatisfies a relationship 4.6≦EFL/AAG≦12.0.
 5. The optical imaging lensset of claim 1, further satisfying a relationship 1.25≦T2/AAG≦4.0. 6.The optical imaging lens set of claim 5, wherein a total thickness ALTof said first lens element, said second lens element and said third lenselement along said optical axis, and an air gap AG12 between said firstlens elements and said second lens element along said optical axissatisfy a relationship 3.5≦ALT/AG12≦15.0.
 7. The optical imaging lensset of claim 1, wherein an effective focal length EFL of the opticalimaging lens set satisfies a relationship EFL/T1≦5.5.
 8. The opticalimaging lens set of claim 7, wherein a total thickness ALT of said firstlens element, said second lens element and said third lens element alongsaid optical axis satisfies a relationship 3.0≦ALT/AAG≦10.0.
 9. Theoptical imaging lens set of claim 1, wherein a total thickness ALT ofsaid first lens element, said second lens element and said third lenselement along said optical axis satisfies a relationship ALT/T1≦3.6. 10.The optical imaging lens set of claim 9, wherein an air gap AG12 betweensaid first lens elements and said second lens element along said opticalaxis satisfies a relationship AG12/T3≦1.0.
 11. The optical imaging lensset of claim 1, wherein an effective focal length EFL of the opticalimaging lens set, and an air gap AG12 between said first lens elementsand said second lens element along said optical axis satisfy arelationship 5.5≦EFL/AG12≦20.0.
 12. The optical imaging lens set ofclaim 11, wherein a focal length f1 of the first lens element, and thefocal length f2 of the second lens element satisfy a relationship|f1/EFL|+|f2/EFL|≦2.0.
 13. The optical imaging lens set of claim 1,wherein a focal length f1 of the first lens element, the focal length f3of the third lens element, and an effective focal length EFL of theoptical imaging lens set satisfy a relationship |f1/EFL|+|f3/EFL|≦2.0.14. An electronic device, comprising: a case; and an image moduledisposed in said case and comprising: an optical imaging lens set ofclaim 1; a barrel for an installation of said optical imaging lens set;a module housing unit for an installation of said barrel; a substratefor an installation of said module housing unit; and an image sensordisposed on the substrate and disposed at an image side of said opticalimaging lens set.